Christmas joke

This was my first Christmas joke since I never joke about Christmas. Somehow it made me wonder how come others can joke about it. It was texted to me just this morning with non-registered number.

A boy during Christmas eve wrote to Santa a letter. "Send me a baby brother!" He wrote. Then Santa wrote back and said "Send me your mother, hehehe".

A time like this, is it proper to joke in this season? have they really understand the true meaning of Christmas or they just occasionally celebrate it because we always celebrate it every year. With this thoughts I rarely see people or even meet a person that will not celebrating Christmas.